img-40The absorption and diffusion of carbon into solid ferrous alloys by heating to a temperature range above the transformation temperature of the alloy in a controlled gas atmosphere to cause the absorption of carbon and nitrogen at the surface Heating takes place in a carbon-rich environment to produce a carbon gradient that extends from the surface into the material. Carbonitrided parts are then cooled at a rate required to produce the desired properties in the material. Carbonitriding is used for thin, hard, wear-resistant cases on parts.